replication/basebackup: use hash table for the exclude list
replication/basebackup: use hash table for the exclude list

The replication basebackup command supports excluding path names with
the EXCLUDE clause, the excluding list used to be stored internally as a
string list and be matched one by one, this can be very inefficient when
the excluding list is large.

Now we store the path names to exclude in a hash table for better
performance.

jmcatamney/gpdb,xinzweb/gpdb,jmcatamney/gpdb,xinzweb/gpdb,jmcatamney/gpdb,xinzweb/gpdb,50wu/gpdb,greenplum-db/gpdb,50wu/gpdb,lisakowen/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,50wu/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,adam8157/gpdb,jmcatamney/gpdb,50wu/gpdb,50wu/gpdb,lisakowen/gpdb,lisakowen/gpdb,xinzweb/gpdb,adam8157/gpdb,jmcatamney/gpdb,adam8157/gpdb,adam8157/gpdb,greenplum-db/gpdb,lisakowen/gpdb,xinzweb/gpdb,50wu/gpdb,lisakowen/gpdb,50wu/gpdb,greenplum-db/gpdb,xinzweb/gpdb,greenplum-db/gpdb,lisakowen/gpdb,adam8157/gpdb,adam8157/gpdb,50wu/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,xinzweb/gpdb,lisakowen/gpdb,xinzweb/gpdb,lisakowen/gpdb,adam8157/gpdb,adam8157/gpdb